1. Field of the Invention
The present invention relates to a semiconductor substrate transport arm for use in a semiconductor substrate transport apparatus for carrying a substrate into and out of a semiconductor substrate processing chamber.
2. Description of the Related Art
FIG. 6 is an outside plan view of a transport arm in a well-known semiconductor substrate transport apparatus. The transport arm has an extensible transport arm 37 capable of moving into and out of a semiconductor substrate processing chamber (not shown) and a semiconductor substrate pan 38 fixed to the leading end of the extensible transport arm 37, for carrying a semiconductor substrate into and out of the semiconductor substrate processing chamber.
In order to carry a semiconductor substrate (not shown) processed in the semiconductor substrate processing chamber, the transport arm 37 is put into the processing chamber and a processed semiconductor substrate is laid on the pan 38 and carried out of the processing chamber by moving the transport arm 37. Outside the semiconductor substrate processing chamber, the processed semiconductor substrate is taken out of the pan 38, and an unprocessed semiconductor substrate is instead laid on the pan 38 and put into the semiconductor processing change. Semiconductor substrates are transported by repeating the above processes.
Since the transport arm in the conventional semiconductor substrate transport apparatus has the above construction, it is necessary to take a processed substrate out of the semiconductor substrate processing chamber before carrying a new semiconductor substrate into the processing chamber, and to perform two extension and contraction operations of the transport arm to process one semiconductor substrate, thereby making the transport time long. Furthermore, it is necessary to open and close an entrance gate of the semiconductor substrate processing chamber in every transport operation in order to prevent the intrusion of dust into the semiconductor substrate processing chamber. The opening and closing operations take substantial time and shorten the operating life of an opening and closing driving portion for the entrance gate.